Field Find Friday*: Arctic Copepods

*yes, I posted this on a Saturday, but I wrote it on a Friday, so it counts

This week’s Field Find are integral links in marine food webs: copepods!3 copepods

Copepods are zooplankton, animals that drift with the currents of the ocean. Other examples of zooplankton are jellies and krill. Numerically, these small crustaceans usually dominate the zooplankton community of any given area. They are key grazers of smaller plankton, and themselves are eaten by a variety of predators, such as small fish, other crustaceans, and baleen whales. By eating organisms that are made up of carbon from the surface ocean, copepods are also very important to the global carbon cycle: copepod dead bodies, exoskeletons, or fecal pellets* that find their way to the ocean floor can be buried, contributing to the role of the ocean floor as a carbon sink.

(* there are scientists who spend most of their careers researching copepod fecal pellets.)

On the Norseman II this past week, we found three species of copepods, pictured left. From top to bottom we have: Calaunus glacialis, Paraeuchaeta sp., Calanus hyperboreus. The tins they are in are a little smaller than the diameter of a soda can.

Calanus glacialis is the most common of these three that we find in the Beaufort Sea.

So many C. glacialis!
So many C. glacialis!

Someone who is familiar with copepods may notice that these guys are rather large. Arctic copepods tend to be literal fatties, storing lots of the energy they gain feeding on spring and summer phytoplankton blooms as lipids. Look at the blobs of oil they leave behind in the tins!

copepod fat

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